Problem: Convert $9\ \dfrac{17}{21}$ to an improper fraction.
Solution: ${9}\ {\dfrac{17}{21}}$ This mixed number is equivalent to ${9} + {\dfrac{17}{21}}$ First, convert the whole part of the mixed number to a fraction with the same denominator $21$ as the fractional part ${9} \times \dfrac{21}{21} = {\dfrac{189}{21}}$ So now we have our number in the form ${\dfrac{189}{21}} + {\dfrac{17}{21}}$ Now, just add the two fractions and simplify! ${\dfrac{189}{21}} + {\dfrac{17}{21}} = \dfrac{206}{21}$